Install the extension

Six steps, about two minutes. You need Chrome on a desktop or laptop — Chrome on phones cannot run extensions at all, so this will not work on a phone.

Chrome will warn you. That is expected.

Because this is installed directly rather than from the Chrome Web Store, Chrome shows "Disable developer mode extensions" every so often. Click Cancel, not Disable. Nothing is broken and nothing needs reinstalling — Chrome shows that for every directly-installed extension.

If you would rather not see it, ask for the Web Store link instead — the same extension, installed the normal way.

  1. 1 Download and unzip

    Download the extension, then unzip it. Chrome loads a folder, not a zip file — this is the step people most often miss.

    Download the extension (.zip)

    Keep the unzipped folder somewhere permanent — Downloads is fine, but if you delete it later the extension stops working. Chrome reads it from that folder every time.

    visa-slot-monitor.zip
    visa-slot-monitor/ unzip, then use THIS folder
    After unzipping you should have a folder, not just the zip.

  2. 2 Open Chrome's extensions page

    Copy this into Chrome's address bar and press Enter:

    chrome://extensions

    Links to chrome:// pages cannot be clicked from a website — Chrome blocks that on purpose — so it has to be pasted.

    chrome://extensions paste here, press Enter

  3. 3 Turn on Developer mode

    Top-right of that page, flip Developer mode on. Two new buttons appear along the top — if they do not, the toggle is still off.

    Extensions Developer mode turn this ON first

  4. 4 Load unpacked

    Click Load unpacked, then choose the folder you unzipped in step 1. Select the folder itself — do not open it and pick a file inside.

    If Chrome says "Manifest file is missing or unreadable", you have selected the wrong folder. You want the one containing manifest.json.

    Load unpacked Pack extension Update click this

  5. 5 Pin it to your toolbar

    Click the puzzle-piece icon beside the address bar and pin Visa Slot Monitor. Pinning matters more than it sounds: the extension's status only shows in its own panel, and unpinned it is easy to forget it is running.

    Visa Slot Monitor pin it

  6. 6 Sign in and start watching

    Open the extension and sign in with the username and password you created on this site. Then pick your locations and start it.

    If you have not made an account yet, do that first — the extension needs it to receive other members' sightings.

    Visa Slot Monitor username password Sign in

If something is wrong

"Manifest file is missing or unreadable"
The wrong folder was selected. Pick the folder that directly contains manifest.json — often there is an extra folder of the same name inside.
Chrome keeps asking to disable developer mode extensions
Expected for directly-installed extensions. Click Cancel. Ask for the Web Store link if you would rather avoid it.
The extension disappeared after restarting Chrome
The folder was moved or deleted. Chrome reads it from that exact location every time it starts. Unzip it again somewhere permanent and repeat step 4.
It says my session expired
Sign in again in the extension panel. Sessions last 90 days, and signing out anywhere ends that session everywhere immediately.
I am not getting notifications
Check Chrome is allowed to show notifications in your operating system settings — macOS and Windows both suppress them independently of Chrome's own setting.

What it can see

The extension only has access to the visa scheduling site and its sign-in page — no other site, no browsing history, no other tabs. Every permission it asks for is explained here, along with what happens to your data.